I've been poking around a Casio rapman
and found some bends that I'd like to share. Most of
them effect the beats. Haven't
found anything to effect the pitch. I don't think that it uses an
RC circuit for timing...

All the components on the circuit board are marked with numbers
(R32, C13, ect) so I'll give the number to be connected.

FB1 - R36 = overtone lead overtop of the beat

R16 - FB1 = loud good sound pitch can be changed by 10k pot or
chirping made with 0.02uf cap)

FB1 - emmiter of trans'r by R36 = complex tone lead created over beat

FB5 - a bunch of different places including the tops of electrolitic
capacitors = by far the best of the bunch. When in "rap" mode
with the beat playing quickly make a connection and it produces
random well timed glitched out loops or crashes out compleatly. Use
on/off sw. to reset.

FB4 - R12/R13/R14 (and a bunch of other places) = pretty much the
same as above but seems to make different sounding loops. Good to
do the above glitch first and then this one after to change it a bit.

Also there are two area's on the left and side of the board with
five or six parallel jumpers (wires). One group running up and down
and the other running side to side. I can't figure out how to
explain which wire is which, but... with a beat playing, poke around
in there, connecting one group to the other, until something good
happens. You should get an overtone that plays along with the
beat. This is also one of my fav's.

Last thing and maybe the best, /.../. The rapman has a builtin "voice effector" which
pitchshits your voice up or down (in octaves or fifths I think). I
bought one of the $2 mikes that they sell in dollar stores around
here and took out the small plastic cylinder that the diaphram is
mounted in and then hooked it up perminantly to the keyboard. The
first cool thing that you can do with this is hum into it like a
kazoo and it makes a wicked, very electronic sounding lead. Doesn't
sound anything like anything make by a mike. The second thing that
you can do with this little mike is hold it infront of the speaker
for some nasty sounds. It picks up whats playing and pitch shifts
it up or down. You can also control the feedback to the point that
you can actually play it. Put the mike close for three counts take
it away for one. /.../

(Disclaimer: shortened by electri-fire. If anyone objects to my copying/editting this post it will be deleted.)

Is there a trick to bringing the output to the input? Do you just wire the positive to the positive? Do you also wire the ground to the ground?

Is there an easy way to introduce a small delay, maybe a cap? Any precautions like resistors and such that need to be added?

Start with inserting a potentiometer between the (positive) in and output.

Suppose you wire it so turning clockwise reduces resistance, so you get more feedback (middle and right solderlug when looking from top side).

When feedback gets too much to your taste, set the pot to the amount of feedback you want at maximum, and measure the resistance between the middle and right lug.
Now insert a resistor of that value (or slightly higher) in series with the pot. This resistor can be inserted anywhere in the feedbackpath, at the circuitboard, at the pot, whatever.

There's no need to do something with the ground connection when feedbacking within one device.

Capacitors can be used, but work as a filter, not delay in the usual sense.

out - in :
It's always asking for trouble to directly wire some output of a device straight into its own input.
Always start with some component in between, pot or resistor.
Sometimes a feedback situation ends up very quickly in a very high frequency oscillation,
which can cause serious power consumption problems, like a CPU running at 100 %, so much current.
These HF signals can be often sufficiently dampened even only by the presence of a resistor,
which has also a capacitance on its own, so acts as a tiny filter too.

Ground :
If the connection is an internal one of the device, there's no need to connect the V- of the output plug to the V- of the input plug.
On the contrary, it could mean a "groundloop" in the system, causing a net-hum (50/60 Hz) on the line.
A caution : Not all outputs, like a headphone plug, have as 'minus' the common power ground V-.
Sometimes it has a "floating zero", which is not the same._________________0.618033988

I was curious about this Rapman, did a search and came upon :
http://www.synthmania.com/rapman.htm
Quite a lot of demo MP3 samples.They are mono, no problem.
But concerning timing, these samples are just sloppy crap.
Just choose a beat from the pattern section, having your player set in 'repeat' mode, knock the beat on the table,
and you'll see what I mean.

Is there some technical circuit available of the Rapman by the way?_________________0.618033988

I'm photographing the process, it wiill make a nice blog entry when I get done.. For now I'm going for a simple glitch crossfader option, internal feedback and magenta spraypaint!! I've got a few spare ones, to experiment further with!

Maybe i could control the pitch shifter by the pwm signal from my arduino! That would make my first casio with usb.. _________________http://husc-sound.com

man those beats that dude sampled are R-R-R-RAW! also hilarious. His tickling of the ivory just pisses me off, but at least he left a bar or two on most of them before he comes in. Cool thread, can't wait to hear the bends.

I have been thinking about taking the ic out and doing something with the twelve stages of pitch shifting, but the ic doesn't have long legs and is (i think) impossible to remove, without damaging it..

It did give me new ideas for g2 patches!

This one was a lot of fun, I found my old Boss DS2 still works, so that one is next, but I'll try and follow up with more experiments with the pitch shifter!!_________________http://husc-sound.com

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